arch/x86/kernel/irq_64.c

   1 /*
   2  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   3  *
   4  * This file contains the lowest level x86_64-specific interrupt
   5  * entry and irq statistics code. All the remaining irq logic is
   6  * done by the generic kernel/irq/ code and in the
   7  * x86_64-specific irq controller code. (e.g. i8259.c and
   8  * io_apic.c.)
   9  */
  10
  11 #include <linux/kernel_stat.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/module.h>
  15 #include <linux/delay.h>
  16 #include <linux/ftrace.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/smp.h>
  19 #include <asm/io_apic.h>
  20 #include <asm/idle.h>
  21 #include <asm/apic.h>
  22
  23 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
  24 EXPORT_PER_CPU_SYMBOL(irq_stat);
  25
  26 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
  27 EXPORT_PER_CPU_SYMBOL(irq_regs);
  28
  29 /*
  30  * Probabilistic stack overflow check:
  31  *
  32  * Only check the stack in process context, because everything else
  33  * runs on the big interrupt stacks. Checking reliably is too expensive,
  34  * so we just check from interrupts.
  35  */
  36 static inline void stack_overflow_check(struct pt_regs *regs)
  37 {
  38 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  39         u64 curbase = (u64)task_stack_page(current);
  40
  41         WARN_ONCE(regs->sp >= curbase &&
  42                   regs->sp <= curbase + THREAD_SIZE &&
  43                   regs->sp <  curbase + sizeof(struct thread_info) +
  44                                         sizeof(struct pt_regs) + 128,
  45
  46                   "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
  47                         current->comm, curbase, regs->sp);
  48 #endif
  49 }
  50
  51 bool handle_irq(unsigned irq, struct pt_regs *regs)
  52 {
  53         struct irq_desc *desc;
  54
  55         stack_overflow_check(regs);
  56
  57         desc = irq_to_desc(irq);
  58         if (unlikely(!desc))
  59                 return false;
  60
  61         generic_handle_irq_desc(irq, desc);
  62         return true;
  63 }
  64
  65 /*
  66  * do_IRQ handles all normal device IRQ's (the special
  67  * SMP cross-CPU interrupts have their own specific
  68  * handlers).
  69  */
  70 asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
  71 {
  72         struct pt_regs *old_regs = set_irq_regs(regs);
  73
  74         /* high bit used in ret_from_ code  */
  75         unsigned vector = ~regs->orig_ax;
  76         unsigned irq;
  77
  78         exit_idle();
  79         irq_enter();
  80
  81         irq = __get_cpu_var(vector_irq)[vector];
  82
  83         if (!handle_irq(irq, regs)) {
  84                 if (!disable_apic)
  85                         ack_APIC_irq();
  86
  87                 if (printk_ratelimit())
  88                         printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
  89                                 __func__, smp_processor_id(), vector);
  90         }
  91
  92         irq_exit();
  93
  94         set_irq_regs(old_regs);
  95         return 1;
  96 }
  97
  98 #ifdef CONFIG_HOTPLUG_CPU
  99 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
 100 void fixup_irqs(void)
 101 {
 102         unsigned int irq;
 103         static int warned;
 104         struct irq_desc *desc;
 105
 106         for_each_irq_desc(irq, desc) {
 107                 int break_affinity = 0;
 108                 int set_affinity = 1;
 109                 const struct cpumask *affinity;
 110
 111                 if (!desc)
 112                         continue;
 113                 if (irq == 2)
 114                         continue;
 115
 116                 /* interrupt's are disabled at this point */
 117                 spin_lock(&desc->lock);
 118
 119                 affinity = desc->affinity;
 120                 if (!irq_has_action(irq) ||
 121                     cpumask_equal(affinity, cpu_online_mask)) {
 122                         spin_unlock(&desc->lock);
 123                         continue;
 124                 }
 125
 126                 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 127                         break_affinity = 1;
 128                         affinity = cpu_all_mask;
 129                 }
 130
 131                 if (desc->chip->mask)
 132                         desc->chip->mask(irq);
 133
 134                 if (desc->chip->set_affinity)
 135                         desc->chip->set_affinity(irq, affinity);
 136                 else if (!(warned++))
 137                         set_affinity = 0;
 138
 139                 if (desc->chip->unmask)
 140                         desc->chip->unmask(irq);
 141
 142                 spin_unlock(&desc->lock);
 143
 144                 if (break_affinity && set_affinity)
 145                         printk("Broke affinity for irq %i\n", irq);
 146                 else if (!set_affinity)
 147                         printk("Cannot set affinity for irq %i\n", irq);
 148         }
 149
 150         /* That doesn't seem sufficient.  Give it 1ms. */
 151         local_irq_enable();
 152         mdelay(1);
 153         local_irq_disable();
 154 }
 155 #endif
 156
 157 extern void call_softirq(void);
 158
 159 asmlinkage void do_softirq(void)
 160 {
 161         __u32 pending;
 162         unsigned long flags;
 163
 164         if (in_interrupt())
 165                 return;
 166
 167         local_irq_save(flags);
 168         pending = local_softirq_pending();
 169         /* Switch to interrupt stack */
 170         if (pending) {
 171                 call_softirq();
 172                 WARN_ON_ONCE(softirq_count());
 173         }
 174         local_irq_restore(flags);
 175 }